Means for impregnating



Nov. l, 1938.

J. E. HOY ET AL' MEANS lFOR IMPREGNATINC- Filed April 22, 1957 149 Ill 6' @@@QQQ @000mb @@QOQ@ @QOOQC CDO) OO 0@ Azz Patented Nov. 1, 1938 UNITED STATES MEANS FOR IMPREGNATING John E. Hoy and claire s.

Harris, Midland,

Mich., assignors to The Dow Chemical Company,.Midland, Mich., a. corporation of Michi'- gall Application April 22, 1937, serial No. 138,340

6 Claims.

Our invention relates to means for impregnating porous bodies with a fluid substance. It relates more particularly to such impregnation with a substance normally solid but fusible and, more specifically, to the impregnation of porous metal parts, e. g. castings of `magnesium base alloys and the like, with a low melting point metal, such as Woods metal.

The treatment of non-ferrous alloy castings, specically magnesium alloy castings, is disclosed in United States Patent No. 2,059,984. 'I'he present invention is directed to the provision of means suitable for impregnation purposes and particularly adapted 'to the process of the above cited patent.

. In working the process of Vthe patent, certain l problems have arisen calling for solution, among which are the provision of means (l) to evacuate the casting or part to be impregnated, and remove gases from the pores thereof, so as to make room for the iluid metal to enter, (2) to apply suitable pressure to force the metal into thepores of the metal part being treated, (3) to fuse and maintain fused the -metal employed, (4) to handle parts of various sizes and contours, either singly or in quantity, at one operation.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawing and the following description setting forth in detail certain means for carrying out the invention, such disclosed means illustrating, however, but one of various-ways in which the principle of the invention may be used.

In said annexed drawing:-

The single figure there appearing is a general vertical transverse cross-section of an impregnating apparatus embodying our invention.

In said drawing, I is an outer cylindrical shell nclosed at the bottom by a head'3. An inner shell 2 0f cylindrical form is sealed to the lower head 3 and to an annular top head 5. The top head 5 and the outer portion of the bottom head 3 form with the shells I and 2 a closed annular' compartment 2 I. The shell 2 with the bottom head 3 and a cover 4 form the inner compartment, or kettle, 22. The head 4 is secured to the top cover 5 by studs and nuts, which may be wing-nuts, as shown at 8. Within the outer compartment 2| is disposed a steam coil\| 5 having a valved inlet I3 and a valved outlet I4, which inlet and outlet extend through the outer shell and are sealed thereinto. A valved nipple I I is sealed into the shells and 2 to communicate with the kettle 22.

(Cl. 91a12.5)

A valved nipple I 2 is sealed into the top head 5 to communicate with the compartment 2|. A valved draw-oil outlet I9 is sealed into the head 3 to communicate with compartment 2|. A valved outlet 20 is sealed into the head 3 to com- 5 muncate with the kettle 22. A capped nipple |Il is sealed into the top head 5 and shell I to communicate with the compartment 2| for the purpose of inspection and supply of metal as required. A basket 6, vwhich may be made of perforated plate or of wire cloth, and may be handled in and out of kettle 22 b y means of. the hooks 1, serves as a container for the castings or other parts to be treated.

'I'he diameters of the shells I and 2 are chosen 15 so that the metal-holding capacity of compartvment 2| is at least as great, and, preferably,

greater, than that of kettle 22. A valve Il is seated into a valve seat 8 sealed to the inner shell 2, the valve stem continuing out to a hand- 20 wheel I6 operating the valve stem through a stuffing box sealed to the outer shell las shown. This valve permits opening and closing a communica- -tlon between compartments 2| and 22.

In the operationof the device, the low melting 25 point metal is introduced through I0, the valve |1 being closed. The metal may be added in the molten form and maintained molten by supplying steam to the coil I5. When the desired amount of metal has been introduced into com- 30 partment 2|, or it has been so iilled, the capped nippleA I0 is closed. The parts to be treated are put into the basket 6 and with the cover 4 removed the basket with its contents is lowered into I the impregnator kettle, after which the cover is 35 applied and bolted down. A vacuum is then apl plied to the inner compartment by way of valvev connection for the purpose of removing oc eluded or absorbed gases from-theparts to be treated. After this has been done the connection 40 may be closed, whereupon the valve I1 is opened, permitting the iluid metal from compartment 2| to enter compartment 224 and risey therein to submerge the parts in the basket 6.1.

When the metal has submerged the parts, the45 valve I1 may be closed and, iLdesired, pressure may be applied through the valve connection by introducing compressed air therethrough to furtheraid in forcing the metal into the parts to be treated. After this has been accomplished, 50 the valve |'I is reopened, whereupon either by the pressure applied through connection or by means of vacuum applied to connection I2 the molten metal is withdrawn from compartment 22 into compartment 2|. When this has been ac- 55 complished, valve I1 is closed, the pressure in the kettle may then be equalized with the room pressure andcover I be removed, the basket'is lifted out, and the cycle of impregnating operations has been completed. Additional metal may be added as desired through connection I0. In case of intermittent use, the metal in compartment 2l may have been allowed to cool and solidify.v It may be remelted by again admitting steam to the coil I5, as previously described. We find that steam `at 150 lbs. gauge pressure is suitable for use in our apparatus employing a 10W melting alloy, such as Woods metal. The parts to be treated may be preheated, if desired, before introducing them into the impregnator. It will be noted that by .use of vacuum and/or compressed air the metal may be transferred from compartment 2| to 22 and vice versa. The parts to be subjected to treatmentmay be put under vacuum to remove occluded gases and when submerged in metal may be put under pressure to aid in forcing the metal into them. It will be noted, further, that the apparatus is self-contained and permits maintaining the metal fused at the proper temperature by the choice of proper pressure of saturated steam. It will be noted that by removing the metal from the kettle compartment 22 to the compartment 2| the apparatus is in condition to receive a fresh charge of untreated parts, which may then be evacuated, permitting the evacuation and impregnation tobe done in one apparatus with but one opening and closing thereof.

Our invention, accordingly, provides a self-contained means for evacuating and impregnating porous bodies with fluid substances, which may be metal, waxes, tars, or other materials, and it is particularly adapted, as described, for the application of the process of the cited patent to the treatment of magnesium base alloy castings.

Other modes of applying the principle of 'our invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We -therefore particularly point out and distinctly claim as our invention:-

1. In means for impregnating, the combination of a kettle adapted 'to hold the'impregnating agent, a sealable cover therefor, a\closed annular compartment' about the kettle, a heating element therein, a valved flow connection between the kettle and said compartment and separate flow connections to the annular compartment and the kettle adapted to connect with a source of vacuum or gas pressure.

2. In means for impregnating, the combination of a kettle adapted to hold the lmpregnating agent, a sealable cover therefor, a closed annular compartment about the kettle, a heating element therein, a valved flow connection between the kettle and said compartment and separate ow connections'to the annular compartment and the kettle adapted to connect with a source of vacuum or gas pressure and a removable 'basket in the kettle adapted to hold an object to be impregnated.

cover sealable thereto, a

3. In means for impregnating, the combination of a kettle adapted to hold the impregnating agent, a sealable cover therefor, a closed annular compartment about the kettle having a capacity preferably in excess \of that of the kettle, a steam heating coil in said compartment, a valved ow connection between the kettle and the compartment so located as to enable transfer of impregnating agent from one to the other,l and separate flow connections to the annular compartment and the kettle adapted to connect with a source of vacuum or ga's pressure. y

4. In meansfor impregnating non-ferrous metal pieces with a low melting metal, the combination of a vertical cylindrical kettle adapted to hold the fused impregnating metal, a cover therefor sealable to the kettle, a closed annular compartment about and concentric with the kettle wall, a steam heating coil therein, a valved ow connection between kettle and annular compartment adapted to enable transfer of fused metal from one to` the other, valved fiow connections to the kettle and the annular compartment adapted for connection with a source of vacuum or pressure and a removable basket in the kettle adapted to hold the work to be impregnated.

5. In means for impregnating solid non-ferrous metal pieces such as magnesium base alloy castings with a low melting alloy, the combination of a vertical cylindrical kettle having a removable cover sealable thereto, a closed annular compartment about and concentric with the cylindrical wall of the kettle, which kettle wall is also the inner wall of said compartment, said compartment' having a capacity preferably in eigcess of that of the kettle, a steam heating coil in said compartment, a valved iiow connection between the kettle and the compartment so located as to enable transfer of fused alloy from the one to the other, valved flow connections to the kettle and to the compartment, respectively, connectible to a source of vacuum or gas pressure, and a sealable opening to s aid compartment for introduction of the impregnatlng agent thereinto.

6. In means for impregnating solid non-ferrous metal pieces such as magnesium base alloy castings with a low melting alloy, the combination of a vertical cylindrical -kettle having a removable closed annular compartment about and concentric with the cylindrical wall of the kettle, which kettle wall is also the inner wall of said compartment, said compartment having .a capacity preferably in excess of that of the kettle a steam heating coil in said compartment, a valved ow connection between the kettle and the compartment so located as to enable transfer of fused alloy from the one to the other, valved flow connections to the kettle and to the compartment, respectively, connectible to a. source of vacuum or pressure, a removable container in the kettle for the pieces to be treated, and a sealable opening to said compartment for introduction of the impregnating thereinto.

JOHN E. HOY. CLAIRE s. HARRIS. 

